Ferment Xylose To Ethanol Hugh Hata Candida Mutation Breeding Research

Xylose fermentation is one of the key factors in the cost of ethanol production with lignocellullose as feedstock. Screening Strains with better xylose fermentation performance is the basis of ethanol production with lignocellullose.In this study, Candida shehatae HDYXHT-01 is mutated by physical mutations and chemical mutation. A strain with high xylose-fermentation rate is screened.Mutation dose and mortality of several physical mutation are studied, which shows that Candida shehatae HDYXHT-01 is mutated by all these 3 mutations. The effect of He-Ne laser is most obvious。The mutant HN-3, which the ethanol yield is 0.3828g/g and the ethanol concentration is 18.49g/L is obtained.HN-3 is mutated by NTG. When the mutagenic dose of NTG final concentration is 0.4mg/mL, the mutation time is 15min, the mortality rate is 75.83% and the positive variable rate is 39.47%. Afte primary screening there are nine mutants which have high yield of ethanol. The ethanol concentration is 24.20g/L, which is 13.20% more than the one of HN-3. The ethanol yield is 0.4375g/g, which is 13.37% more than the one of HN-3.NTG-2 is checked with genetic stability by the method of continuous passage. The result shows that after 10 consecutive passages, there's no significant change among the strains.NTG-2 is fermented in flask with the time 48h. The ethanol concentration, xylose utilization rate, ethanol yield and ethanol production rate are 24.16g/L,69.26%,0.4360g/g and 0.7075g/ (L.h).Thus, physical factors and chemical mutagenesis can improve the yield of ethanol and the utilization of xylose of Candida shehatae HDYXHT-01, which is the basis of lignocellullose ethanol industry.